After the steaks, chops, breasts, ribs, thighs, hams, tenderloins and briskets are removed, there's a fair amount of gristle, fat and offal remaining on a butchered animal, and early on, people realized this could be put to good use. One of these products is the hot dog, a classic of pre-cooked, processed meat.

Trimmings

The National Hot Dog & Sausage Council (NHDSC) notes that hot dogs, whether regular, turkey, pork or beef, begin with "trimmings." A purposely-vague word, trimmings come in lots of shapes and sizes.

Pre-cooking

Because of the butchering process, the leftovers used in products like hot dogs often have a fair amount of bacteria, and so pre-cooking helps eliminate that. In addition, pre-cooking has the added benefit of helping to separate the remaining muscle meat, fat and connective tissues from the head and feet bones. Cooking also makes the trimmings more manageable.

Because of the different sizes and types of carcasses, there are different pre-cooking times for different animals (and different parts), although it typically occurs within the range of 150 to 190 degrees Fahrenheit.

Hot Dog Production

Like many other products, such as bologna and liver sausage, hot dogs and frankfurters are created by "meat emulsion," although as the FAO notes, "meat batter" might be a more accurate term.

Higher quality products are made from top quality meats and no chemicals. Examples include kosher, all beef hot dogs that have no by-products, fillers or artificial colors or flavors.

Less expensive types of hot dogs will have chemicals, fats and water binding agents added, and for many of these, the production process is simple:

First pork and/or beef trimmings are ground up in a machine and then extruded through a metal sieve-like device so they resemble ground hamburger meat. At this point, ground chicken trimmings (if any) are added, and together, the mixture is blended (emulsified) until it looks like the aforementioned meat batter.

Now salt, ground spices and food starches (if you made this at home, you might use bread crumbs, flour or oatmeal) are added, along with some water and corn syrup or another sweetener. Toward the end of the process, more water is added, to get the batter to the proper consistency (no one wants a dry wiener).

The batter is "pureed again [and] the excess air is vacuumed out." Next the emulsified meat is pumped into casings (usually cellulose but sometimes natural), and the strings of dogs are hung on racks and fully cooked in a smoke house. Sometimes hardwood smoke is added. Later, the dogs are showered in cold, salted water, and then, if cellulose casings were used, put through a peeler to remove the casings (natural casings are left on).

Remember, "natural casings" means the intestine of an animal that have been thoroughly cleaned and processed.

Finally, finished dogs are inspected by hand, and only "flawless" tubed meat is routed to yet another machine where the dogs are grouped for packing.

The name "frankfurter" comes from the fact that a popular hot dog-like sausage was originally made in Frankfurt Germany (Frankfurter meaning "of Frankfurt"). The name was brought over to America sometime in the late 19th century from German immigrants who were familiar with the Frankfurter sausage.

In U.S. grocery stores alone, about $1.7 billion per year are spent on hot dogs.

Los Angelenos eat the most hot dogs, purchasing over 95 million in 2012. In fact, at Dodgers Stadium alone, in 2013, they consumed over 2 million. Of course, dogs are popular at all MLB parks, and in 2014, the NHDSC estimates that baseball fans will eat over 20 million dogs at the 30 parks across the country.

The record for hot dog consumption is held by Joey Chestnut, who stuffed 69 dogs into his maw in 10 minutes at Nathan's Famous Fourth of July Hot Dog Eating Contest in Coney Island on July 4, 2013. To train for such an event, Joey fasts for three days and gulps water to stretch out his esophageal muscles. (See: The Origin of Competitive Eating Contests)

According to the USDA, an average "meat" frankfurter has 5.34 grams of protein, 13.4 grams of fat and, surprisingly (not!) no dietary fiber. A typical hot dog will also have 567 mg of sodium (the RDA is between 1,500 and 2,300 mg). On the other hand, an average dog will have calcium (51 mg), potassium (79 mg), magnesium (8 mg) and folate (3 ug), as well as trace amounts of iron, zinc, thiamin, riboflavin, niacin, B-6, B-12 and E.